We will enter patients with surgically resectable lung cancer into a randomized prospective study of the effect of intrapleural BCG as a regional form of immunotherapy. This treatment is based on the observation that intrapleural infection seems to improve the survival fraction in lung cancer patients. The use of orally administered isoniazid in combination with intrapleural BCG improves its efficiency in experimental animal tumors. We use isoniazid in combination with BCG in our human study. Preliminary analysis of the first 100 patients to enter this study suggests that intrapleural BCG improves the survival fraction of lung cancer patients with Stage I disease. BIBLIOGRAPHIC REFERENCES: Maver, C., and McKneally M.F.: Phytohemagglutinin skin tests in lung cancer patients treated with BCG. American Association for Cancer Research. Denver, May 18-21, 1977. Abstract, in press. Meier, P, Filardi M., Jennings R., McKeneally MF: INH augmentation of immune responses to sheep red blood cells and pulmonary tumors. For presentation at the 61st Annual Meeting of the Federation of American Societies for Experimental Biology, Chicago, Illinois, April 1-8, 1977, in press.